1. Field of the Invention
The present invention relates to a pulper in a stock preparation system, and, more particularly, to a pulper providing a high consistency output.
2. Description of the Related Art
A fiber stock preparation system is used to make a fiber suspension from a source of fiber such as wood. The fiber stock preparation system receives the raw source of fiber, breaks the raw source of fiber into individual fibers suspended in a liquid such as water, and separates contaminants from the fiber suspension.
A fiber stock preparation system as described above typically includes a pulper which assists in breaking down the raw source of fiber into individual fibers. A pulper typically includes a rotatable element within a chamber which imparts mechanical forces to the source of fiber and breaks the source of fiber into individual fibers. The pulped fiber is transported downstream to other mechanical devices within the stock preparation system. For example, the pulped fiber may be further processed within a disperger. A disperger receives the pulped fiber and removes contaminants from the fiber suspension and thoroughly mixes chemicals within the fiber suspension.
Pulpers of conventional design as described above effectively pulp the raw source of fiber into individual fibers. However, it may be desirable to provide a higher consistency output from the pulper depending upon the particular application.
What is needed in the art is a pulper which is configured to provide a higher consistency output.
The present invention provides a pulper in a fiber stock preparation system having a tank with particularly configured inner walls, baffles within the tank, and a particularly configured rotor within the tank which provide a high consistency and high quality output.
The invention comprises, in one form thereof, a pulper for pulping a fiber source including a tank and a rotor. The tank has a plurality of annular-shaped inner walls defining a chamber. The plurality of walls include a first wall, second wall, third wall and forth wall which are sequentially vertically adjoining relative to each other. Each of the walls are disposed at an angle relative to a vertical reference. The first wall is disposed at an angle of between 45 and 70xc2x0 relative to the vertical reference. The second wall is disposed at an angle of between 20 and 45xc2x0 relative to the vertical reference. The third wall is disposed generally parallel to the vertical reference. The forth wall is disposed at an angle of between 10 and 30xc2x0 relative to the vertical reference. The tank further includes two baffles within the chamber which inhibit rotational movement of the fiber source within the chamber.
An advantage of the present invention is that a high consistency and high quality stock is outputted from the pulper.
Another advantage is that the shape of the inner walls, the baffles within the tank, and the configuration of the rotor coact to provide the high consistency output.